| Trial | Location | Design | Treatment; no. of patients | Duration of intervention | ||
|---|---|---|---|---|---|---|
| Sulfonylurea | Metformin | Total | ||||
| ADOPT, 2006 (20)– (26) | North America, Europe and Canada | Parallel; blinding of investigators and participants | 1447 | 1455 | 2902 | 4 yr |
| Campbell et al., 1994 (27) | United Kingdom | Parallel; open label | 24 | 24 | 48 | 1 yr |
| Collier et al., 1989 (28) | NR | Parallel; open label | 12 | 12 | 24 | 6 mo |
| DeFronzo et al., 1995 (29) | United States | Parallel; blinding of investigators and participants | 209 | 210 | 419 | 29 wk |
| Derosa et al., 2004 (42) | Italy | Parallel; open label | 81 | 83 | 164 | 12 mo (+ 8-wk titration period) |
| Hermann et al., 1991a (30) | Sweden | Crossover; open label | 10* | 12* | 25* | 6 mo |
| Hermann et al., 1991b (31)– (34) | Sweden | Parallel; blinding of investigators and participants | 34 | 38 | 72 | 6 mo + 2–12 wk titration period |
| Kamel et al., 1997 (35) | Turkey | Parallel; blinding of investigators and participants | 17† | 6 | 23 | 24 wk |
| Lawrence et al., 2004 (36) | United Kingdom | Parallel; open label | 22 | 21 | 43 | 24 wk |
| Tang et al., 2004 (41) | China | Parallel; open label | 33 | 29 | 62 | 6 mo |
| Tessier et al., 1999 (37) | Canada | Parallel; open label | 19 | 20 | 39 | 24 wk |
| Tosi et al., 2003 (38) | Italy | Crossover; blinding of investigators and participants | 22 | 22 | 44 | 6 mo |
| UKPDS 34, 1998 (2), (39), (40) | United Kingdom | Parallel; open label | 277 | 342 | 619 | 10.7 yr |
| Yamanouchi et al., 2005 (43) | Japan | Parallel; NR (we assume open label) | 37 | 39 | 76 | 12 mo |
Note: ADOPT = A Diabetes Outcome Progression Trial, NR = not reported, UKPDS = United Kingdom Prospective Diabetes Study. *Number of participants randomly selected for each intervention arm not reported; only those who completed the trial. †The 17 participants in the sulfonylurea arm were given either gliclazide (9 participants) or glibenclamide (8 participants).